A prior art firefighting agent is made from a material having fire-extinguishing properties and consists of microcapsules of fire-extinguishing composition embedded in a polymeric binder. The microcapsules are microspheres consisting of spherical gelatin shells, each enclosing a liquid firefighting agent such as any substances in the class of halo-organic compounds of the formula C3F7I, or CnF2n+2, or (C2F5)2N(CmF2m+1), wherein n=5-7 and m=1-2, that are released automatically upon heating. The microcapsules have a size of 100 to 400 μm (that is, from 10−4 m to 4·10−4 m) and open up within the temperature range of 130 to 149° C. and 166 to 190° C. (Patent RU2161520, 1998).
The prior art agent is deficient because making gelatin shells for microcapsules used therein to micro-capsulize a fire-extinguishing composition is a technologically complicated and expensive process that raises significantly the costs of products manufactured from this material. Besides, the prior art agent has a very high triggering threshold (at a temperature of 130° C.) that is not always acceptable.
The closest related prior art invention of the claimed agent is an autonomous firefighting agent made from a material having fire-extinguishing properties that comprises microcapsules containing a fire-extinguishing composition, said microcapsules having a size ranging from 2 to 100 μm (that is, from 2·10−6 m to 10−5 m), said material being halocarbon enclosed in a polymeric shell of polyurea and/or polyurethane, and a binder such as a polymeric resin. The prior art agent has a mass content of halocarbon varying between 70% and 90%. The material having fire-extinguishing properties is applied to a solid-phase support, for example, a metal substrate (Patent RU90994, 2009).
The prior art agent has capsules opening within the temperature range of 110 to 165° C. and is manufactured in an advanced process at lower costs.
The prior art agent, though, has a number of drawbacks. For example, the fire-fighting layer may crack and flake off the substrate surface over time and/or with fluctuations in the temperature and moisture content of the environment. As a result, the fire-extinguishing properties of the agent deteriorate and it may fail to function in response to ignition. Furthermore, for the substrate material, for example, metal, coated with the fire-extinguishing composition to adhere firmly to the walls of an object protected, the surface to which the agent is attached must meet certain requirements, such as be smooth and level, a requirement that is not always attainable in practice. It has also been demonstrated practically that a material having fire-extinguishing properties exhibits its best properties when the content of halocarbon therein is other than in the range of 70% to 90%.